Pressurized dispensing systems such as aerosols are known to be a useful way to deliver certain compositions. Various types of dispensing systems have been described. See, e.g., U.S. Pat. Nos. 5,560,544; 5,305,930; 7,637,399; 7,464,839; 7,143,959; 6,827,239; 6,695,227; 6,588,631; 6,113,070; 6,338,442; 3,613,728; 3,430,819; 3,257,044; 5,918,782; 6,030,682; 7,143,959; and 5,617,978, U.S. Publ. No. 2002 079679; 2010 0004647; and WO Pubs. 2010/005946; 2007/015665; and 2006/071512. Many pressurized dispensing systems typically release composition when the user actuates the device, thereby allowing a volume of composition to be expelled from a dispensing orifice or nozzle. One problem with pressurized dispensing systems is that the composition contained within the flow path following actuation can undesirably exit the dispensing orifice after use. This can be particularly problematic for aerosols which dispense fluids or gels. Even more problematic is where the fluids or gels contain foaming agents, such as for shaving foams, hair mousses, post foaming shaving gels, and so forth, and/or other volume changing aerosol dispense products.
With foaming compositions, the pressure within the container keeps the composition in a non-foamed state. Once the composition is dispensed from the device, the composition is subjected to atmospheric pressure allowing the blowing agents to cause the composition to foam. Any composition trapped within the flow path would also contain blowing agent. Since the flow path is not maintained under pressure, this trapped volume of composition would eventually begin to foam as any residual pressure built up in the flow path dissipates to reach the environmental pressure around the device. Since the volume of the foam can be many times the volume of the composition in liquid or gel state, the foam would push itself out of the flow path through any dispensing orifice.
Attempts to minimize this problem have been described. For example, US 2009/0230156 discloses a spring loaded piston that opens to release gel upon actuation and shuts/seals the flowpath when the actuator is released. This approach seals the flowpath thereby forming the flowpath into a pressure vessel and maintaining the blowing agent into the liquid state. This system can, however, be cost prohibitive and can be subject to performance issues.
U.S. Pat. No. 7,104,424 B2 discloses a flexible flowpath that shuts the end of the flowpath after actuation and allows the gel remaining in the flowpath to expand and foam but remain contained within the flowpath. These systems, however, may be problematic as foamed composition trapped within the flexible flowpath may remain under pressure, causing the actuator to spit already foamed composition on the next dispensing and potentially dispense the composition in inconsistent physical forms due in part to the collapsing of the flexible flow path. Further, the use of flexible and soft materials, such as thermoplastic elastomer, can be costly and complex to assemble.
In US Publ. No. 2007/0090133 to Macleod et al, discloses an actuator comprising a flow conduit mated with a valve stem which is displaceable. Upon actuation, the flow conduit is displaced out of a closed position and actuates the valve stem. It is alleged that the actuator traps residual foamable composition in the flow conduit between the closed valve and the closure when the actuating pressure is released and the flow conduit and the closer return under the action of the bias to their closed position. This system, however, still requires the composition to gradually break down into smaller volumes of liquid as the trapped propellant evaporates and escapes. As such, drooling can still occur, albeit at a potentially slower rate. Further, this system uses a vertical valve spring which can be costly and the valve seal is located in the vertical flow path portion, leaving any horizontal portions subject to post actuation foaming.
In yet another attempt to minimize this problem is to decrease the volume of composition in the flow path. Although this may reduce the amount of material which can eventually foam within the flow path, drooling can still occur. These and other dispensing systems are known but still suffer from various issues such as undesirable drooling, excessive or under spraying, as well as product clogging at the dispense orifice by dried or crystallized product. The present invention addresses one or more of the issues encountered with current systems.